This solar film is actually a solar filter, but it is different from a traditional solar filter. It is PET-coated aluminum foil film. High Quality:the solar film is not easy to be damaged, and it is suitable for long-term use in natural environments, especially when taking pictures, without fear of wind and rain. The main difference from the traditional Bard film is that the sun looks red via its, Via traditional Bard film looks like gray sun. Sharper photos: the lens for sharper, clearer images. for Celestron 22097 127SLT and size-related products. To safely observe the sun without damaging your eyes. Size Chart: Inner Diameter 145mm/5.71inch Outer Diameter: 150mm/5.91inch Thickness: 25mm/0.98inch Package Includes: 1 Piece Solar Filter Sun Film